Acylselenoureato bis(chelates) of lead: synthesis, structural characterization and microwave-assisted formation of PbSe nano- and microstructures

Abstract

We report the synthesis of three lead(II) bis(acylselenoureato) complexes (1a–3a), which were prepared by the reaction of the respective acylselenourea compounds ArC(O)NHC(Se)NR₂ [Ar = 4-MeC₆H₄, R = Et (1); 4-ClC₆H₄, R = ⁿBu (2), ⁱBu (3)] with Pb(OAc)₂. All three compounds were confirmed by NMR spectroscopy, elemental analysis and single crystal X-ray diffraction. Furthermore, the lead(II) complex 3a was transformed into PbSe nanostructures in a microwave-assisted synthesis using either a mixture of trioctylphosphine (TOP), octadecene (ODC) and the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMIm][NTf₂], a mixture of [BMIm][NTf₂] and propylene carbonate (PC), pure [BMIm][NTf₂] or pure PC. The analyses of the resulting particle dispersions indicated formation of either small PbSe nanoparticles of 19 nm, PbSe submicro-cubes between 178 nm and 366 nm as well as strongly intergrown structures depending on the stabilizing reagent used during the synthesis. The prepared PbSe particle suspensions were characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectrocopy (EDX) as well as by selected area electron diffraction (SAED).